Path Length Checker is a stand-alone app that allows you to specify a root directory, and it gives you back a list of all paths (i.e. files and directories) in that root directory and their lengths. It includes features such as pattern matching and min/max length constraints, as well as the ability to specify a string that should replace the root directory in the results brought back, allowing you to quickly see path lengths if you were to move the files/folders to another location. Includes both GUI and command-line interfaces.
There is currently a bug
with the Path Length Checker tool where it is not able to process paths in Windows restricted directories (e.g. C:\Documents and Settings). In the meantime you can use this PowerShell script
to get those path lengths.